5 Several common useful Lua functions
11 Copyright 2008 Steven Barth <steven@midlink.org>
13 Licensed under the Apache License, Version 2.0 (the "License");
14 you may not use this file except in compliance with the License.
15 You may obtain a copy of the License at
17 http://www.apache.org/licenses/LICENSE-2.0
19 Unless required by applicable law or agreed to in writing, software
20 distributed under the License is distributed on an "AS IS" BASIS,
21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22 See the License for the specific language governing permissions and
23 limitations under the License.
27 local io = require "io"
28 local math = require "math"
29 local table = require "table"
30 local debug = require "debug"
31 local ldebug = require "luci.debug"
32 local string = require "string"
33 local coroutine = require "coroutine"
35 local getmetatable, setmetatable = getmetatable, setmetatable
36 local rawget, rawset, unpack = rawget, rawset, unpack
37 local tostring, type, assert = tostring, type, assert
38 local ipairs, pairs, loadstring = ipairs, pairs, loadstring
39 local require, pcall, xpcall = require, pcall, xpcall
41 --- LuCI utility functions.
45 -- Pythonic string formatting extension
47 getmetatable("").__mod = function(a, b)
50 elseif type(b) == "table" then
51 return a:format(unpack(b))
59 -- Class helper routines
62 -- Instantiates a class
63 local function _instantiate(class, ...)
64 local inst = setmetatable({}, {__index = class})
73 --- Create a Class object (Python-style object model).
74 -- The class object can be instantiated by calling itself.
75 -- Any class functions or shared parameters can be attached to this object.
76 -- Attaching a table to the class object makes this table shared between
77 -- all instances of this class. For object parameters use the __init__ function.
78 -- Classes can inherit member functions and values from a base class.
79 -- Class can be instantiated by calling them. All parameters will be passed
80 -- to the __init__ function of this class - if such a function exists.
81 -- The __init__ function must be used to set any object parameters that are not shared
82 -- with other objects of this class. Any return values will be ignored.
83 -- @param base The base class to inherit from (optional)
84 -- @return A class object
88 return setmetatable({}, {
89 __call = _instantiate,
94 --- Test whether the given object is an instance of the given class.
95 -- @param object Object instance
96 -- @param class Class object to test against
97 -- @return Boolean indicating whether the object is an instance
100 function instanceof(object, class)
101 local meta = getmetatable(object)
102 while meta and meta.__index do
103 if meta.__index == class then
106 meta = getmetatable(meta.__index)
113 -- Scope manipulation routines
116 --- Create a new or get an already existing thread local store associated with
117 -- the current active coroutine. A thread local store is private a table object
118 -- whose values can't be accessed from outside of the running coroutine.
119 -- @return Table value representing the corresponding thread local store
120 function threadlocal()
123 local function get(self, key)
124 local c = coroutine.running()
125 local thread = coxpt[c] or c or 0
126 if not rawget(self, thread) then
129 return rawget(self, thread)[key]
132 local function set(self, key, value)
133 local c = coroutine.running()
134 local thread = coxpt[c] or c or 0
135 if not rawget(self, thread) then
136 rawset(self, thread, {})
138 rawget(self, thread)[key] = value
141 setmetatable(tbl, {__index = get, __newindex = set, __mode = "k"})
148 -- Debugging routines
151 --- Write given object to stderr.
152 -- @param obj Value to write to stderr
153 -- @return Boolean indicating whether the write operation was successful
155 return io.stderr:write(tostring(obj) .. "\n")
158 --- Recursively dumps a table to stdout, useful for testing and debugging.
159 -- @param t Table value to dump
160 -- @param maxdepth Maximum depth
161 -- @return Always nil
162 function dumptable(t, maxdepth, i, seen)
164 seen = seen or setmetatable({}, {__mode="k"})
166 for k,v in pairs(t) do
167 perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
168 if type(v) == "table" and (not maxdepth or i < maxdepth) then
171 dumptable(v, maxdepth, i+1, seen)
173 perror(string.rep("\t", i) .. "*** RECURSION ***")
181 -- String and data manipulation routines
184 --- Escapes all occurrences of the given character in given string.
185 -- @param s String value containing unescaped characters
186 -- @param c String value with character to escape (optional, defaults to "\")
187 -- @return String value with each occurrence of character escaped with "\"
188 function escape(s, c)
190 return s:gsub(c, "\\" .. c)
193 --- Create valid XML PCDATA from given string.
194 -- @param value String value containing the data to escape
195 -- @return String value containing the escaped data
196 local function _pcdata_repl(c)
197 local i = string.byte(c)
199 if ( i >= 0x00 and i <= 0x08 ) or
200 ( i >= 0x0B and i <= 0x0C ) or
201 ( i >= 0x0E and i <= 0x0F ) or
202 ( i >= 0x26 and i <= 0x27 ) or
203 ( i == 0x7F ) or ( i == 0x22 ) or
204 ( i == 0x3C ) or ( i == 0x3E )
206 return string.format("&#%i;", i)
212 function pcdata(value)
213 return value and tostring(value):gsub("[&\"'<>%c]", _pcdata_repl)
216 --- Strip HTML tags from given string.
217 -- @param value String containing the HTML text
218 -- @return String with HTML tags stripped of
219 function striptags(s)
220 return pcdata(s:gsub("</?[A-Za-z][A-Za-z0-9:_%-]*[^>]*>", " "):gsub("%s+", " "))
223 --- Splits given string on a defined separator sequence and return a table
224 -- containing the resulting substrings. The optional max parameter specifies
225 -- the number of bytes to process, regardless of the actual length of the given
226 -- string. The optional last parameter, regex, specifies whether the separator
227 -- sequence is interpreted as regular expression.
228 -- @param str String value containing the data to split up
229 -- @param pat String with separator pattern (optional, defaults to "\n")
230 -- @param max Maximum times to split (optional)
231 -- @param regex Boolean indicating whether to interpret the separator
232 -- pattern as regular expression (optional, default is false)
233 -- @return Table containing the resulting substrings
234 function split(str, pat, max, regex)
254 local s, e = str:find(pat, c, not regex)
256 if s and max < 0 then
259 t[#t+1] = str:sub(c, s and s - 1)
261 c = e and e + 1 or #str + 1
262 until not s or max < 0
267 --- Remove leading and trailing whitespace from given string value.
268 -- @param str String value containing whitespace padded data
269 -- @return String value with leading and trailing space removed
271 return (str:gsub("^%s*(.-)%s*$", "%1"))
274 --- Count the occurences of given substring in given string.
275 -- @param str String to search in
276 -- @param pattern String containing pattern to find
277 -- @return Number of found occurences
278 function cmatch(str, pat)
280 for _ in str:gmatch(pat) do count = count + 1 end
284 --- Parse certain units from the given string and return the canonical integer
285 -- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
286 -- Recognized units are:
287 -- o "y" - one year (60*60*24*366)
288 -- o "m" - one month (60*60*24*31)
289 -- o "w" - one week (60*60*24*7)
290 -- o "d" - one day (60*60*24)
291 -- o "h" - one hour (60*60)
292 -- o "min" - one minute (60)
293 -- o "kb" - one kilobyte (1024)
294 -- o "mb" - one megabyte (1024*1024)
295 -- o "gb" - one gigabyte (1024*1024*1024)
296 -- o "kib" - one si kilobyte (1000)
297 -- o "mib" - one si megabyte (1000*1000)
298 -- o "gib" - one si gigabyte (1000*1000*1000)
299 -- @param ustr String containing a numerical value with trailing unit
300 -- @return Number containing the canonical value
301 function parse_units(ustr)
308 y = 60 * 60 * 24 * 366,
309 m = 60 * 60 * 24 * 31,
310 w = 60 * 60 * 24 * 7,
318 gb = 1024 * 1024 * 1024,
320 -- storage sizes (si)
323 gib = 1000 * 1000 * 1000
326 -- parse input string
327 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
329 local num = spec:gsub("[^0-9%.]+$","")
330 local spn = spec:gsub("^[0-9%.]+", "")
332 if map[spn] or map[spn:sub(1,1)] then
333 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
343 -- also register functions above in the central string class for convenience
344 string.escape = escape
345 string.pcdata = pcdata
346 string.striptags = striptags
349 string.cmatch = cmatch
350 string.parse_units = parse_units
353 --- Appends numerically indexed tables or single objects to a given table.
354 -- @param src Target table
355 -- @param ... Objects to insert
356 -- @return Target table
357 function append(src, ...)
358 for i, a in ipairs({...}) do
359 if type(a) == "table" then
360 for j, v in ipairs(a) do
370 --- Combines two or more numerically indexed tables and single objects into one table.
371 -- @param tbl1 Table value to combine
372 -- @param tbl2 Table value to combine
373 -- @param ... More tables to combine
374 -- @return Table value containing all values of given tables
375 function combine(...)
376 return append({}, ...)
379 --- Checks whether the given table contains the given value.
380 -- @param table Table value
381 -- @param value Value to search within the given table
382 -- @return Boolean indicating whether the given value occurs within table
383 function contains(table, value)
384 for k, v in pairs(table) do
392 --- Update values in given table with the values from the second given table.
393 -- Both table are - in fact - merged together.
394 -- @param t Table which should be updated
395 -- @param updates Table containing the values to update
396 -- @return Always nil
397 function update(t, updates)
398 for k, v in pairs(updates) do
403 --- Retrieve all keys of given associative table.
404 -- @param t Table to extract keys from
405 -- @return Sorted table containing the keys
409 for k, _ in kspairs(t) do
416 --- Clones the given object and return it's copy.
417 -- @param object Table value to clone
418 -- @param deep Boolean indicating whether to do recursive cloning
419 -- @return Cloned table value
420 function clone(object, deep)
423 for k, v in pairs(object) do
424 if deep and type(v) == "table" then
430 return setmetatable(copy, getmetatable(object))
434 --- Create a dynamic table which automatically creates subtables.
435 -- @return Dynamic Table
437 return setmetatable({}, { __index =
439 return rawget(tbl, key)
440 or rawget(rawset(tbl, key, dtable()), key)
446 -- Serialize the contents of a table value.
447 function _serialize_table(t, seen)
448 assert(not seen[t], "Recursion detected.")
455 for k, v in pairs(t) do
456 if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
457 k = serialize_data(k, seen)
458 v = serialize_data(v, seen)
459 data = data .. ( #data > 0 and ", " or "" ) ..
460 '[' .. k .. '] = ' .. v
467 local v = serialize_data(t[i], seen)
468 idata = idata .. ( #idata > 0 and ", " or "" ) .. v
471 return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
474 --- Recursively serialize given data to lua code, suitable for restoring
475 -- with loadstring().
476 -- @param val Value containing the data to serialize
477 -- @return String value containing the serialized code
480 function serialize_data(val, seen)
481 seen = seen or setmetatable({}, {__mode="k"})
485 elseif type(val) == "number" then
487 elseif type(val) == "string" then
489 elseif type(val) == "boolean" then
490 return val and "true" or "false"
491 elseif type(val) == "function" then
492 return "loadstring(%q)" % get_bytecode(val)
493 elseif type(val) == "table" then
494 return "{ " .. _serialize_table(val, seen) .. " }"
496 return '"[unhandled data type:' .. type(val) .. ']"'
500 --- Restore data previously serialized with serialize_data().
501 -- @param str String containing the data to restore
502 -- @return Value containing the restored data structure
503 -- @see serialize_data
505 function restore_data(str)
506 return loadstring("return " .. str)()
511 -- Byte code manipulation routines
514 --- Return the current runtime bytecode of the given data. The byte code
515 -- will be stripped before it is returned.
516 -- @param val Value to return as bytecode
517 -- @return String value containing the bytecode of the given data
518 function get_bytecode(val)
521 if type(val) == "function" then
522 code = string.dump(val)
524 code = string.dump( loadstring( "return " .. serialize_data(val) ) )
527 return code and strip_bytecode(code)
530 --- Strips unnescessary lua bytecode from given string. Information like line
531 -- numbers and debugging numbers will be discarded. Original version by
532 -- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
533 -- @param code String value containing the original lua byte code
534 -- @return String value containing the stripped lua byte code
535 function strip_bytecode(code)
536 local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
539 subint = function(code, i, l)
542 val = val * 256 + code:byte(i + n - 1)
547 subint = function(code, i, l)
550 val = val * 256 + code:byte(i + n - 1)
557 strip_function = function(code)
558 local count, offset = subint(code, 1, size)
559 local stripped, dirty = string.rep("\0", size), offset + count
560 offset = offset + count + int * 2 + 4
561 offset = offset + int + subint(code, offset, int) * ins
562 count, offset = subint(code, offset, int)
565 t, offset = subint(code, offset, 1)
569 offset = offset + size + subint(code, offset, size)
571 offset = offset + num
572 elseif t == 254 or t == 9 then
573 offset = offset + lnum
576 count, offset = subint(code, offset, int)
577 stripped = stripped .. code:sub(dirty, offset - 1)
579 local proto, off = strip_function(code:sub(offset, -1))
580 stripped, offset = stripped .. proto, offset + off - 1
582 offset = offset + subint(code, offset, int) * int + int
583 count, offset = subint(code, offset, int)
585 offset = offset + subint(code, offset, size) + size + int * 2
587 count, offset = subint(code, offset, int)
589 offset = offset + subint(code, offset, size) + size
591 stripped = stripped .. string.rep("\0", int * 3)
592 return stripped, offset
595 return code:sub(1,12) .. strip_function(code:sub(13,-1))
600 -- Sorting iterator functions
603 function _sortiter( t, f )
606 for k, v in pairs(t) do
612 table.sort( keys, f )
616 if _pos <= #keys then
617 return keys[_pos], t[keys[_pos]]
622 --- Return a key, value iterator which returns the values sorted according to
623 -- the provided callback function.
624 -- @param t The table to iterate
625 -- @param f A callback function to decide the order of elements
626 -- @return Function value containing the corresponding iterator
628 return _sortiter( t, f )
631 --- Return a key, value iterator for the given table.
632 -- The table pairs are sorted by key.
633 -- @param t The table to iterate
634 -- @return Function value containing the corresponding iterator
636 return _sortiter( t )
639 --- Return a key, value iterator for the given table.
640 -- The table pairs are sorted by value.
641 -- @param t The table to iterate
642 -- @return Function value containing the corresponding iterator
644 return _sortiter( t, function (a,b) return t[a] < t[b] end )
649 -- System utility functions
652 --- Test whether the current system is operating in big endian mode.
653 -- @return Boolean value indicating whether system is big endian
655 return string.byte(string.dump(function() end), 7) == 0
658 --- Execute given commandline and gather stdout.
659 -- @param command String containing command to execute
660 -- @return String containing the command's stdout
661 function exec(command)
662 local pp = io.popen(command)
663 local data = pp:read("*a")
669 --- Return a line-buffered iterator over the output of given command.
670 -- @param command String containing the command to execute
672 function execi(command)
673 local pp = io.popen(command)
675 return pp and function()
676 local line = pp:read()
687 function execl(command)
688 local pp = io.popen(command)
694 if (line == nil) then break end
702 --- Returns the absolute path to LuCI base directory.
703 -- @return String containing the directory path
705 return require "luci.fs".dirname(ldebug.__file__)
710 -- Coroutine safe xpcall and pcall versions modified for Luci
712 -- coxpcall 1.13 - Copyright 2005 - Kepler Project (www.keplerproject.org)
714 -- Copyright © 2005 Kepler Project.
715 -- Permission is hereby granted, free of charge, to any person obtaining a
716 -- copy of this software and associated documentation files (the "Software"),
717 -- to deal in the Software without restriction, including without limitation
718 -- the rights to use, copy, modify, merge, publish, distribute, sublicense,
719 -- and/or sell copies of the Software, and to permit persons to whom the
720 -- Software is furnished to do so, subject to the following conditions:
722 -- The above copyright notice and this permission notice shall be
723 -- included in all copies or substantial portions of the Software.
725 -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
726 -- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
727 -- OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
728 -- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
729 -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
730 -- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
731 -- OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
733 local performResume, handleReturnValue
734 local oldpcall, oldxpcall = pcall, xpcall
736 setmetatable(coxpt, {__mode = "kv"})
738 -- Identity function for copcall
739 local function copcall_id(trace, ...)
743 --- This is a coroutine-safe drop-in replacement for Lua's "xpcall"-function
744 -- @param f Lua function to be called protected
745 -- @param err Custom error handler
746 -- @param ... Parameters passed to the function
747 -- @return A boolean whether the function call succeeded and the return
748 -- values of either the function or the error handler
749 function coxpcall(f, err, ...)
750 local res, co = oldpcall(coroutine.create, f)
753 local newf = function() return f(unpack(params)) end
754 co = coroutine.create(newf)
756 local c = coroutine.running()
757 coxpt[co] = coxpt[c] or c or 0
759 return performResume(err, co, ...)
762 --- This is a coroutine-safe drop-in replacement for Lua's "pcall"-function
763 -- @param f Lua function to be called protected
764 -- @param ... Parameters passed to the function
765 -- @return A boolean whether the function call succeeded and the returns
766 -- values of the function or the error object
767 function copcall(f, ...)
768 return coxpcall(f, copcall_id, ...)
771 -- Handle return value of protected call
772 function handleReturnValue(err, co, status, ...)
774 return false, err(debug.traceback(co, (...)), ...)
776 if coroutine.status(co) == 'suspended' then
777 return performResume(err, co, coroutine.yield(...))
783 -- Resume execution of protected function call
784 function performResume(err, co, ...)
785 return handleReturnValue(err, co, coroutine.resume(co, ...))